Question 1

Calculate the molality of a solution formed by dissolving 27.8 g of LiI in 500.0 mL of water. A) 0.254 mol kg^-1 B) 0.394 mol kg^-1 C) 0.556 mol kg^-1 D) 0.241 mol kg^-1 E) 0.415 mol kg^-1

Accepted Answer

The answer of Calculate the molality of a solution formed...

Question 2

What is the term for the amount of solute in moles per litre of solution?
A) molality
B) molarity
C) mole fraction
D) mole percent
E) mass percent

Accepted Answer

The term for the amount of solute in moles per litre of solution is molarity, which is represented by the symbol M. Molality (A) is the amount of solute in moles per kilogram of solvent, mole fraction (C) is the ratio of moles of solute to the total number of moles in the solution, mole percent (D) is the mole fraction multiplied by 100, and mass percent (E) is the mass of solute in grams divided by the mass of solution in grams, multiplied by 100.

Question 3

Identify the compound whose solubility is least affected by temperature. A) Na₂SO₄ B) K₂Cr₂O₇ C) KNO₃ D) KClO₃ E) NaCl

Accepted Answer

NaCl is a simple, small ionic compound that is highly soluble in water and its solubility is not very affected by temperature. The other compounds listed have more complex structures and/or contain elements that may have varying solubilities with temperature changes.

Question 4

Which of the following should have the largest Henry's law constant (k_H) in water? A) Ar B) CO C) Xe D) CH₃CH₃ E) CO₂

Accepted Answer

The answer of Which of the following should have the...

Question 5

Which of the following compounds is highly soluble at room temperature? A) Na₂SO₄ B) K₂Cr₂O₇ C) KNO₃ D) KClO₃ E) NaCl

Accepted Answer

The answer of Which of the following compounds is highly...

Question 6

Which of the following concentration units are temperature dependent?
A) mole fraction
B) molality
C) mass percent
D) molarity
E) None of the above

Accepted Answer

Molarity is temperature dependent because it is defined as moles of solute per liter of solution, and the volume of a solution can change with temperature.

Question 7

Which of the following should have the smallest Henry's law constant (k_H) in water at 25 °C? A) O₂ B) CO₂ C) N₂ D) He E) NH₃

Accepted Answer

Henry's law constant is related to the solubility of a gas in a liquid. The smaller the size of the gas molecule, the less soluble it is in water. Therefore, the gas with the smallest molecule size, which is helium (He), should have the smallest Henry's law constant in water at 25 °C.

Question 8

Which of the following statements is TRUE?
A) In general, the solubility of a solid in water decreases with increasing temperature.
B) In general, the solubility of a gas in water decreases with increasing temperature.
C) The solubility of a gas in water usually increases with decreasing pressure.
D) The solubility of an ionic solid in water decreases with increasing temperature.
E) None of the above statements is true.

Accepted Answer

In general, the solubility of a gas in water decreases with increasing temperature. This is because gases tend to become less soluble in liquids as the temperature increases, due to the increased kinetic energy allowing the gas molecules to escape more easily from the solution.

Question 9

Determine the solubility of CO₂ in soda water at 25 °C if the pressure of CO₂ is 5.2 bar. The Henry's law constant for carbon dioxide in water at this temperature is 3.4 × 10^-2 mol L^-1 bar^-1. A) 0.15 mol L^-1 B) 0.57 mol L^-1 C) 0.65 mol L^-1 D) 0.18 mol L^-1 E) 0.29 mol L^-1

Accepted Answer

The answer of Determine the solubility of CO₂ in soda...

Question 10

Determine the partial pressure of oxygen necessary to form an aqueous solution that is 4.1 × 10^-4mol L^-1 O₂ at 25 °C. The Henry's law constant for oxygen in water at 25 °C is 1.3 × 10^-³ mol L^-1 bar^-1. A) 1.9 bar B) 0.53 bar C) 0.24 bar D) 0.77 bar E) 0.32 bar

Accepted Answer

The answer of Determine the partial pressure of oxygen necessary...

Question 11

What mass (in g) of NH₃ must be dissolved in 475 g of methanol to make a 0.250 mol kg^-1 solution? A) 2.02 g B) 4.94 g C) 1.19 g D) 8.42 g E) 1.90 g

Accepted Answer

The correct answer is A because 2.02 g of NH3 must be dissolved in 475 g of methanol to make a 0.250 mol kg-1 solution.

Question 12

Which of the following statements is TRUE?
A) The solubility of a gas is not dependent on either temperature or pressure.
B) The solubility of a gas is highly dependent on pressure.
C) The solubility of a gas is highly dependent on both pressure and temperature.
D) The solubility of a gas is highly dependent on temperature.
E) None of the above.

Accepted Answer

According to Henry's law, the solubility of a gas in a liquid is directly proportional to its partial pressure above the liquid. Thus, the solubility of a gas is highly dependent on pressure. Additionally, the solubility of a gas decreases with increasing temperature. Therefore, the solubility of a gas is highly dependent on both pressure and temperature.

Question 13

Which of the following should have the largest Henry's law constant (k_H) in water at 25 °C? A) O₂ B) CO₂ C) N₂ D) He E) NH₃

Accepted Answer

Henry's law constant is dependent on the gas solubility and the gas pressure. The gas solubility depends on the intermolecular forces between the gas and the solvent molecules. Larger and more polar molecules with stronger intermolecular forces will have a higher Henry's law constant. Among the given choices, E (NH₃) is the largest and most polar molecule with the strongest intermolecular forces, making it the best choice for having the largest Henry's law constant in water at 25 °C.

Question 14

Determine the Henry's law constant for ammonia in water at 25 °C if an ammonia pressure of 0.022 bar produces a solution with a concentration of 1.3 mol L^-1. A) 59 mol L^-1 bar^-1 B) 0.017 mol L^-1 bar^-1 C) 0.029 mol L^-1 bar^-1 D) 35 mol L^-1 bar^-1 E) 0.038 mol L^-1 bar^-1

Accepted Answer

Henry's law constant (k) is calculated using the formula k = concentration/pressure. Here, k = 1.3 mol L^-1 / 0.022 bar = 59 mol L^-1 bar^-1.

Question 15

Calculate the mass of oxygen (in mg) dissolved in a 5.00 L bucket of water exposed to a pressure of 1.13 bar of air. Assume the mole fraction of oxygen in air to be 0.21 and the Henry's law constant for oxygen in water at this temperature to be 1.3 × 10^-3 mol L^-1 bar^-1. A) 49.4 mg B) 23.5 mg C) 9.87 mg D) 27.3 mg E) 13.7 mg

Accepted Answer

To find the mass of oxygen dissolved, use Henry's law: C = kP. Here, C is the concentration of dissolved oxygen, k is the Henry's law constant, and P is the partial pressure of oxygen. P = 0.21 × 1.13 bar = 0.2373 bar. C = 1.3 × 10^-3 mol/L/bar × 0.2373 bar = 3.0859 × 10^-4 mol/L. For 5 L, moles of O2 = 5 × 3.0859 × 10^-4 = 1.54295 × 10^-3 mol. Mass = moles × molar mass of O2 (32 g/mol) = 1.54295 × 10^-3 × 32 = 0.0493744 g = 49.4 mg.

Question 16

Identify the gas that is dissolved in carbonated sodas.
A) carbon dioxide
B) oxygen
C) nitrogen
D) carbon monoxide
E) hydrogen

Accepted Answer

The gas dissolved in carbonated sodas is carbon dioxide.

Question 17

Determine the solubility of N₂ in water exposed to air at 25 °C if the atmospheric pressure is 1.2 bar. Assume that the mole fraction of nitrogen is 0.78 in air and the Henry's law constant for nitrogen in water at this temperature is 6.1 × 10^-4 mol L^-1bar^-1. A) 1.5 × 10^-4 mol L^-1 B) 6.5 × 10^-4 mol L^-1 C) 5.7 × 10^-4 mol L^-1 D) 1.8 × 10^-4 mol L^-1 E) 3.6 × 10^-4 mol L^-1

Accepted Answer

The solubility of nitrogen in water at 25 °C and 1.2 bar can be calculated using Henry's law as follows: p_n = x_n * K_H where p_n is the partial pressure of nitrogen in air, x_n is the mole fraction of nitrogen in air, and K_H is the Henry's law constant for nitrogen in water at this temperature. Substituting the given values, we get: p_n = 0.78 * 6.1 × 10^-4 mol L^-1bar^-1 p_n = 4.758 × 10^-4 bar Now, we can use Dalton's law of partial pressures to find the total pressure of nitrogen in water: P_n = p_n / (1 - sol) where P_n is the total pressure of nitrogen in water and sol is the solubility of nitrogen in water (in mol/L). Rearranging the equation, we get: sol = 1 - p_n / P_n Since the atmospheric pressure is 1.2 bar and nitrogen constitutes 78% of air, the total pressure of nitrogen in air is 0.78 * 1.2 = 0.936 bar. Substituting the values, we get: sol = 1 - 4.758 × 10^-4 / 0.936 sol = 5.65 × 10^-5 mol L^-1 Rounding to the appropriate number of significant figures, we get the final answer as 5.7 × 10^-4 mol L^-1, which is choice C.

Question 18

Identify the compound whose solubility decreases with increasing temperature. A) Na₂SO₄ B) K₂Cr₂O₇ C) KNO₃ D) KClO₃ E) NaCl

Accepted Answer

The solubility of Na2SO4 decreases with increasing temperature due to the exothermic nature of its dissolution process.

Question 19

What is the term for the amount of solute in moles per kilogram of solvent?
A) molality
B) molarity
C) mole fraction
D) mole percent
E) mass percent

Accepted Answer

The term for the amount of solute in moles per kilogram of solvent is called molality. Molarity is the term for the amount of solute in moles per liter of solution. Mole fraction refers to the ratio of the number of moles of one component to the total number of moles in the solution. Mole percent refers to the percentage of the total number of moles in the solution that is made up of a particular component. Mass percent is the term used for the mass of solute per 100 grams of solution.

Question 20

Parts per billion requires a multiplication factor of ________. A) 10^-6 B) 10^-3 C) 10³ D) 10⁶ E) 10⁹

Accepted Answer

The answer of Parts per billion requires a multiplication factor...

Quiz 12: Solutions

Calculate the molality of a solution formed by dissolving 27.8 g of LiI in 500.0 mL of water.

What is the term for the amount of solute in moles per litre of solution?

Identify the compound whose solubility is least affected by temperature.

Which of the following should have the largest Henry's law constant (kH) in water?

Which of the following compounds is highly soluble at room temperature?

Which of the following concentration units are temperature dependent?

Which of the following should have the smallest Henry's law constant (kH) in water at 25 °C?

Which of the following statements is TRUE?

Determine the solubility of CO2 in soda water at 25 °C if the pressure of CO2 is 5.2 bar. The Henry's law constant for carbon dioxide in water at this temperature is 3.4 × 10-2 mol L-1 bar-1.

Determine the partial pressure of oxygen necessary to form an aqueous solution that is 4.1 × 10-4 mol L-1 O2 at 25 °C. The Henry's law constant for oxygen in water at 25 °C is 1.3 × 10-3 mol L-1 bar-1.

What mass (in g) of NH3 must be dissolved in 475 g of methanol to make a 0.250 mol kg-1 solution?

Which of the following statements is TRUE?

Which of the following should have the largest Henry's law constant (kH) in water at 25 °C?

Determine the Henry's law constant for ammonia in water at 25 °C if an ammonia pressure of 0.022 bar produces a solution with a concentration of 1.3 mol L-1.

Calculate the mass of oxygen (in mg) dissolved in a 5.00 L bucket of water exposed to a pressure of 1.13 bar of air. Assume the mole fraction of oxygen in air to be 0.21 and the Henry's law constant for oxygen in water at this temperature to be 1.3 × 10-3 mol L-1 bar-1.

Identify the gas that is dissolved in carbonated sodas.

Determine the solubility of N2 in water exposed to air at 25 °C if the atmospheric pressure is 1.2 bar. Assume that the mole fraction of nitrogen is 0.78 in air and the Henry's law constant for nitrogen in water at this temperature is 6.1 × 10-4 mol L-1 bar-1.

Identify the compound whose solubility decreases with increasing temperature.

What is the term for the amount of solute in moles per kilogram of solvent?

Parts per billion requires a multiplication factor of ________.

Which of the following should have the largest Henry's law constant (k_H) in water?

Which of the following should have the smallest Henry's law constant (k_H) in water at 25 °C?

Determine the solubility of CO₂ in soda water at 25 °C if the pressure of CO₂ is 5.2 bar. The Henry's law constant for carbon dioxide in water at this temperature is 3.4 × 10^-2 mol L^-1 bar^-1.

Determine the partial pressure of oxygen necessary to form an aqueous solution that is 4.1 × 10^-4mol L^-1 O₂ at 25 °C. The Henry's law constant for oxygen in water at 25 °C is 1.3 × 10^-³ mol L^-1 bar^-1.

What mass (in g) of NH₃ must be dissolved in 475 g of methanol to make a 0.250 mol kg^-1 solution?

Which of the following should have the largest Henry's law constant (k_H) in water at 25 °C?

Determine the Henry's law constant for ammonia in water at 25 °C if an ammonia pressure of 0.022 bar produces a solution with a concentration of 1.3 mol L^-1.

Calculate the mass of oxygen (in mg) dissolved in a 5.00 L bucket of water exposed to a pressure of 1.13 bar of air. Assume the mole fraction of oxygen in air to be 0.21 and the Henry's law constant for oxygen in water at this temperature to be 1.3 × 10^-3 mol L^-1 bar^-1.

Determine the solubility of N₂ in water exposed to air at 25 °C if the atmospheric pressure is 1.2 bar. Assume that the mole fraction of nitrogen is 0.78 in air and the Henry's law constant for nitrogen in water at this temperature is 6.1 × 10^-4 mol L^-1bar^-1.